GPAtlas🧭 When to suspect
A non-blanching rash is one that does not fade when pressed – confirm it with the glass (tumbler) test, pressing a clear glass firmly over the lesions and watching whether they disappear. Petechiae are pinpoint non-blanching spots < 2 mm; purpura are 2 mm–1 cm; ecchymoses (bruises) are > 1 cm.
The single judgement that governs everything is whether the patient is acutely unwell or not. An acutely unwell patient with a non-blanching rash has meningococcal sepsis until proven otherwise and needs a 999 ambulance. A patient who looks well with an unexplained non-blanching rash is not in the clear – the rash still demands urgent investigation to exclude leukaemia and thrombocytopenia.
Strongly suspect meningococcal disease with any of: purpura (lesions > 2 mm), a rapidly spreading non-blanching petechial or purpuric rash, or any features of meningitis combined with a non-blanching rash. Crucially, do not rule out meningococcal disease just because there is no rash, and remember the rash can change from blanching to non-blanching over hours.
| Clinical picture | Think of | Action |
|---|---|---|
| Non-blanching rash + systemically unwell (fever, tachycardia, hypotension, cold peripheries, drowsiness) | Meningococcal sepsis | 999 now; benzylpenicillin only if transfer delayed |
| Well child, isolated petechiae/bruising, often days after a viral illness or immunisation | ITP – but leukaemia must be excluded | Immediate specialist assessment |
| Palpable purpura over buttocks/extensor lower limbs + abdominal pain or arthralgia | IgA vasculitis (formerly HSP) | Urgent paediatric review; urine & BP |
| Petechiae on face/neck, above the nipple line after forceful coughing or vomiting; patient well | Mechanical (SVC distribution) | Benign if FBC normal – reassure |
| Crops of purpura on extensor forearms/dorsum of hands in an older adult with fragile skin | Senile (actinic) purpura | Reassure; skin protection |
| Bruising/petechiae in sites or patterns that do not fit the history in a child | Consider non-accidental injury | Follow safeguarding procedures |
Raise suspicion further with relevant risk factors: missed immunisations, asplenia/hyposplenism or complement deficiency, being a student in shared accommodation, recent contact or a local outbreak (meningococcal); and a personal or family history of bleeding or clotting disorders, anticoagulant or antiplatelet use, liver disease, or recently started medicines (bleeding/thrombocytopenia).
Source: NICE NG240 · NICE NG12 · NICE NG143
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